Arterial switch operation for transposition of great arteries (D-TGA)
Arterial switch operation for transposition of great arteries (D-TGA): Transposition of great arteries (D-TGA) with intact ventricular septum is one of the few conditions which require surgical intervention in the early neonatal period. If a successful balloon atrial septostomy can be done to improve the mixing at the atrial level, surgery need by done within two to three weeks. Otherwise the neonate may have to be taken up within the first week itself, if there is severe hypoxemia.
Arterial switch operation (Jatene’s) is done under cardiopulmonary bypass and involves the restoration of ventriculoarterial concordance. Sternotomy is done under general anaesthesia. The ventilation may be suspended momentarily during sternotomy to prevent lung injury with the sternotomy saw. In case the right ventricle is opened inadvertently during sternotomy (quite rare) urgent percutaneous femoro-femoral bypass may be instituted.
Arterial duct is dissected, ligated and divided. Pulmonary artery and its proximal branches are also dissected for mobilization.
Cardiopulmonary bypass (CPB) is instituted after total body heparinization. Arterial cannula is inserted into the aorta as distally as possible and venous cannula can be inserted in the right atrial appendage and inferior vena cava. Cardioplegia can be either cold blood or crystalloid, the former being better. Cardioplegia solution is rich in potassium to produce cardiac arrest in diastole. External cooling of the heart with cold saline is done prior to administration of cardioplegia. Cardioplegia may be administered through a cannula inserted proximal to the aortic cross clamp. The right atrium is vented to drain the coronary venous blood which would otherwise distend the heart during administration of cardioplegia. Cardioplegia can be repeated administered every 20 minutes. Circulatory cooling is done using the hypothermia unit attached to the heart lung machine. Cardioplegia ensures myocardial protection due to the lowered oxygen demand. Venting of the left ventricle can be done by a catheter placed across the interatrial septum through the right atriotomy.
Aorta and pulmonary arteries are transected and transferred to the corresponding ventricles by the LeCompte manoeuvre. Coronaries are transferred along with a button of tissue to the neo-aorta. The arterial suturing can be done with 6-0 Prolene.
Occasionally it may be difficult to close the sternum initially due to tissue swelling in extreme neonates. In that case skin closure with bandaging and secondary closure may have to be resorted to.
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